Soil sampling tools and devices are used for a variety of purposes, e.g., to obtain samples for soil moisture content or to detect and analyze a VOC which may have permeated the soil. And soil cores are removed for other reasons unrelated to VOC analysis. Examples of soil coring and sampling tools are shown in U.S. Pat. Nos. 3,326,049 (Eley); 3,444,938 (Ballman); 3,497,018 (Schultz et al.) and 4,989,678 (Thompson) and others.
It is common knowledge that tanks for storing liquids may, over time, develop a leak. If the tank is above ground, the leak is usually observed rather soon after its onset and not much damage results. On the other hand, there is an already-substantial and growing awareness that certain types of liquid storage tanks placed underground have a greater-than-normal propensity to deteriorate and leak. Such types include tanks made of common sheet steel which had no protective coating or from which such coating has been eaten away. And a substantial factor contributing to the risk of tank leakage is that with an underground tank, leakage is not visible. Usually, such leakage can only be detected by excavation and testing.
And the risks are enormous. Undetected leaks of underground storage tanks can and do contaminate soil and potable water supplies, the latter by polluting underground aquifers from which a great deal of drinking water is drawn. Recent legislation recognizes risks presented by leaking underground storage tanks and provides for remediation of damage caused by such leaks. Because of the number of gasoline service stations and private fuel and solvent storage tanks, leakage of petroleum distillates and hydrocarbons is a particularly significant problem.
Good remediation requires that personnel be able to accurately determine the nature of the fluid involved in the leak and the extent (depth and area) to which such fluid has permeated the earth and, perhaps, polluted water. Such determination depends in large part upon the availability of high quality test instruments and the ability to preserve the integrity of a soil sample. Preservation of integrity involves (among other factors) prevention of evaporation of VOCs in a soil sample. The efforts of earlier workers in this regard have not been entirely satisfactory.
For example, known sampling tools are made of metal, preferably stainless steel. In instances where dozens or even hundreds of soil samples are taken at a particular site, the sheer aggregate weight of the tools imposes a burden upon their users.
Another disadvantage of known metal sampling tools is that they are made by machining metal stock. The cost of such tools, especially if made available in quantities of hundreds of tools per site, is quite considerable.
Still another disadvantage of known soil sampling tools is that after use, they must be thoroughly washed to help avoid so-called "cross-contamination," i.e., contamination of the next-successive sample collected by residue left on the tool from the preceding sample collected. And even though washing is a major factor in preventing such cross-contamination, the time required to perform thorough washing of, e.g., several hundred tools, can be substantial.
Yet another disadvantage of known tools involves the fact that over time and repeated use, critical VOC-sealing surfaces may become scratched or otherwise impaired. Surface impairments such as scratches can form small passages from which VOC vapors can escape, impairing the integrity of the sample.
An improved tool which addresses and overcomes disadvantages of prior art tools would be an important advance in the art.